In a principal aspect, the present invention relates to an improved double acting diaphragm pump and, more particularly, to a double acting diaphragm pump wherein the pumping force upon the fluid which is to be pumped exceeds the force attributable to pneumatic or other fluid pressure directly on the diaphragm. Such pumps are often called 2:1, 3:1, etc. diaphragm pumps.
Heretofore a double acting diaphragm pump typically includes first and second, main diaphragms each of which separate a pump chamber from a pressure chamber. The pump chamber receives the fluid or material pumped or transported and the pressure chamber receives pressurized fluid such as air that acts upon the diaphragm to effect flexure and thus pumping action. The separate diaphragms for a double acting diaphragm pump are generally connected by a shaft so that the diaphragms will reciprocate in unison in a manner which alternately provides pumping of fluid from one of the pump chambers or the other. Since the two pump chambers are connected to a common inlet manifold and a common outlet manifold, a continuous flow of fluid into the inlet manifold and from the outlet manifold is provided by the described operation of the pump.
The force to effect the pumping action by such a pump is equal to the area of the diaphragm times the pressure per unit of area of the diaphragm. Thus, in a double acting diaphragm pump which provides a continuous output, the pumping force is limited by the area of the main diaphragm.
There has, therefore, been a need to enhance the pumping force. Heretofore a known double acting diaphragm pump which provides for enhanced pumping force on fluid in the pumping chamber includes a separate, enlarged fluid pressure diaphragm mechanically connected to a spaced main pumping diaphragm by a shaft. The separate fluid pressure diaphragm has a surface area which is greater than the main pumping diaphragm thus providing an increased pumping force through the mechanical shaft connection to the main pumping diaphragm.
Nonetheless, there has remained a need to provide an improved, double acting, diaphragm pump of simplified construction and operation, having a fewer number of parts than prior art double acting diaphragm pumps, and also capable of providing enhanced pressure for pumping fluid.